It is known to forge a long tube, e.g. a piece of pipe, from a prepunched or tubular workpiece. To this end the tubular workpiece is gripped by a handler and brought into the working space of a forging machine. Before the tubular workpiece is forged in the forging machine a mandrel on a rod is inserted axially through a guide passage in the handler and into a bore of the tubular workpiece. Tools of the forging machine plastically deform the metal of the workpiece so it internally conforms to the outside shape of the mandrel, such deformation normally thinning the walls and lengthening the workpiece.
The forging machine has several tools or forging jaws acting radially on the tubular workpiece. The tubular workpiece fed or loaded on the charging side upstream of the forging machine, for example, by pivoting is gripped and held by the workpiece handler, e.g. by grippers, as is known for example from U.S. Pat. No. 5,218,855. In the tubular workpiece thus held by the workpiece handler for forge handling, the rod with the mandrel on its end, which can be acted on axially by a control drive, is moved through a hollow passage of the workpiece handler.
The centered insertion of the mandrel into the tubular workpiece hereby is fairly difficult, especially in view of the great length of the rod, which promotes deflection.
It is known from DE 200 07 682 to guide the rod in a holding fixture provided for the axial support and rotational engagement of the workpiece, which holding fixture is supported in a clamping head housing in a rotationally and axially displaceable manner. The holding fixture has for this purpose a guide sleeve in which a bushing surrounding a guide section of the rod is rotatably fixed. The disadvantage of this solution is that the rod guidance is very complex, which results in corresponding costs.